Systems and methods for selecting an access node and/or cell sector for handover of a wireless device

ABSTRACT

Systems and methods are described for performing handover of a wireless device to a target Access Node (AN) sector. Beam-form capable sectors of one or more target ANs may be selected from a pool of candidate sectors. At least one of the selected sectors may be prioritized (e.g., over the other sectors) based on an open beam-form seat. Handover of the wireless device from a first AN to the prioritized sector may be performed.

This patent application is a continuation of U.S. patent applicationSer. No. 15/404,470, filed on Jan. 12, 2017, which is incorporated byreference in its entirety for all purposes.

TECHNICAL BACKGROUND

As wireless networks develop, spatial filtering creates opportunities tocombat multipath fading and/or to mitigate co-channel interference atwireless devices. For example, in Heterogeneous Networks (HetNet), smartantenna arrays (e.g., switched-beam, phased array, and/or adaptive arraysystems) may be deployed at Access Nodes (ANs) to direct beams towardselect wireless devices (or geographic areas) within a radio range ofthe ANs to increase signal-capturing power at the wireless devices,while suppressing and/or nullifying signals emanating to/from otherwireless devices and/or ANs (i.e., “beamforming”). Smart antenna arraysare also used by wireless networks to improve long-range communications.Because ANs support a restricted number of “beam-formed” wirelessdevices (e.g., as a function of Sounding Reference Signal (SRS)period(s)), handover of a beam-formed (or candidate) wireless device totarget ANs and/or cell sectors having high beam-form loads may result inundesirable loss of throughput and/or Quality of Service (QoS) for thebeam-formed (or candidate) wireless device.

Overview

Systems and methods are described for performing handover of a wirelessdevice to a target AN sector. For example, beam-form capable sectors ofone or more target ANs may be selected from a pool of candidate sectors.At least one of the selected sectors may be prioritized (e.g., over theother sectors) based on an open beam-form seat. Handover of the wirelessdevice from a first AN to the prioritized sector may be performed.

In another embodiment, it may be verified that a first sector offersbeamforming. A list of prioritized neighboring sectors may be generatedbased on the verification; the neighboring sectors may be selected(e.g., for prioritization) based on an open beamforming seat. Abeam-form load may be calculated for each of the prioritized neighboringsectors. The neighboring sector having a beam-form load meeting a setcriteria may be selected for handover of the wireless device.

In yet another embodiment, candidate sectors may be selected from a poolof neighboring AN sectors; the candidate sectors are prioritized basedon an open beam-form seat. An amount of beam-formed wireless devices maybe calculated for each of the prioritized candidate sectors. Theprioritized candidate sector with a least amount of beam-formed wirelessdevices may be selected for handover of the wireless device. Handover ofthe wireless device from a first sector of a first AN to the selectedcandidate sector may be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exemplary communication system for prioritizingANs and/or cell sectors for handover of a beam-formed (or candidate)wireless device in a wireless network.

FIG. 1B illustrates an exemplary AN equipped with a smart antenna array.

FIG. 2 illustrates a flow chart of an exemplary method for prioritizingANs and/or cell sectors for handover of a beam-formed (or candidate)wireless device in a wireless network.

FIG. 3 illustrates another exemplary communication system forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device in a wireless network.

FIG. 4 illustrates another flow chart of an exemplary method forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device in a wireless network.

FIG. 5 illustrates an exemplary processing node.

DETAILED DESCRIPTION

As wireless networks develop, spatial filtering creates opportunities tocombat multipath fading and/or to mitigate co-channel interference atwireless devices. Referring to FIG. 1A, in operation, smart antennaarrays (e.g., switched-beam, phased array, and/or adaptive arraysystems) are configured at ANs 104, 106 to exploit a diversity effect atANs 104, 106 (i.e., Tx/Rx of multiple radio frequencies at Tx/Rxantennas 122, illustrated in FIG. 1B, of the smart antenna arraysconfigured at ANs 104, 106 to decrease error and increase data speedbetween ANs 104, 106 and wireless devices 102, 102A) to boostsignal-capturing power at and/or improve long-range communications forwireless devices 102, 102A (or select geographic areas) operating withina radio range (i.e., minimum usable signal area) of ANs 104, 106 on thedownlink (DL), while suppressing and/or nullifying signals emanatingto/from other wireless devices and/or ANs.

For example, wireless network 108 (or network node 110) may equip thesmart antenna arrays (as opposed to omnidirectional and/or sectorizedantenna arrays) deployed at ANs 104, 106 with intelligent beam-steering(i.e., with signal processing algorithms which can easily locate andtrack wireless devices 102, 102A) such that ANs 104, 106 can radiatebeams and/or beam patterns toward select wireless devices 102, 102Aoperating within a radio range of the ANs 104, 106 on the DL (i.e.,intelligent choice), while suppressing and/or nullifying signalsemanating to/from other wireless devices and/or ANs.

In one embodiment, as wireless device 102 moves along a path within aradio range of AN 104, AN 104 may instruct the wireless device 102 tomeasure and/or report various detectable signal properties (e.g.,Channel Quality Indicators (CQI), Received Signal Strength Indicators(RSSI), Reference Signal Received Power (RSRP), Reference SignalReceived Quality (RSRQ), Signal-to-Interference-Plus-Noise Ratio (SINR),etc.), Cell-IDs, etc., broadcasted by ANs 104, 106 positioned at varyinggeographic locations within wireless network 108 on the uplink (UL) atAN 104. Wireless device 102 may also report an availability of uplinkair-interface Sounding Reference Signal (SRS) resources (e.g., SRSresource blocks allocatable to wireless device 102) on the UL at AN 104.AN 104 collects the reported signal properties, Cell-IDs, and/or SRS' atTx/Rx antennas 122 of the smart antenna array (i.e., collectedinformation) and uses the collected information to estimate (ordetermine) a Direction of Arrival (DoA) for signals emanating fromwireless device 102 using various techniques such as Multiple SignalClassification (MUSIC) and/or through estimation of signal parametersvia rotational invariance techniques (ESPRIT), etc. The DoA of thesignals (or similarly the Angle of Arrival) are used by AN 104 tocalculate beamforming weights; AN 104's smart antenna array uses thecalculated beamforming weights to radiate beams and/or beam patterns(e.g., formed by aligning beam main-lobes to the DoA at beam-select 124and/or beam-former 126) on the DL toward wireless device 102 (e.g., byweighting the magnitude and phase of individual antenna signalsbroadcast by Tx/Rx antennas 122 of AN 104's antenna array at beam-select124 and/or beam-former 126). AN 104 may continuously control and/orradiate (i.e., direct) beams and/or beam patterns toward wireless device102 as wireless device 102 moves along a path within the radio range ofAN 104 (i.e., according to the movement of wireless device 102) toincrease signal-capturing power at and/or improve long-rangecommunications for wireless device 102. AN 104 can use the Tx/Rxantennas 122 of the smart antenna array to suppress and/or nullifyvarious signals emanating to/from other wireless devices and/or ANs byapplying, for example, a beam pattern null from the smart antenna arrayin the direction of the interfering signals.

Because ANs 104, 106 support a restricted number of “beam-formed”wireless devices (e.g., as a function of SRS period(s)), AN 104 maychoose to “handoff” beam-formed (or candidate) wireless devices 102 to atarget AN 106 and/or cell sector of a target AN 106 based on an openbeamforming seat. For example, in an exemplary embodiment, AN 104 mayuse reported signal properties (e.g., CQI, RSSI, RSRP, RSRQ, SINR,etc.), Cell-IDs, etc., associated with target ANs 106 and/or cellsectors of the target ANs 106 collected (or measured) at wireless device102 and/or SRS' to estimate (or determine) a DoA for signals emanatingfrom wireless device 102 at AN 104. AN 104 may use the reported signalproperties (e.g., CQI, RSSI, RSRP, RSRQ, SINR, etc.), Cell-IDs, etc., ofthe target ANs 106 and/or cell sectors of the target ANs 106 todetermine a pool of candidate ANs 106 and/or cell sectors of candidateANs 106 for handover of wireless device 102. From the pool of candidateANs 106 and/or cell sectors of candidate ANs 106, which may benon-beam-form capable, AN 104 selects only beam-form capable candidateANs 106 and/or cell sectors of the beam-form capable candidate ANs 106.The selected beam-form capable candidate ANs 106 and/or cell sectors ofthe beam-form capable candidate ANs 106 may be prioritized (i.e., overother beam-form capable ANs and/or cell sectors) at AN 104 for handoverof wireless device 102 based on an open beamforming seat. AN 104 mayperform a handover of wireless device 102 to the prioritized beam-formcapable candidate AN 106 and/or cell sector of the beam-form capablecandidate AN 106.

FIG. 1A illustrates an exemplary communication system 100 forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device in a wireless network. FIG. 1B illustrates anexemplary AN equipped with a smart antenna array. System 100 cancomprise wireless devices 102, 102A, 102B, ANs 104, 106, 106A, wirelessnetwork 108, and network node 110. Other network elements may be presentin the system 100 to facilitate communication but are omitted forclarity, such as controller nodes, base stations, base stationcontrollers, gateways, Mobile-Switching Centers (MSC), DispatchApplication Processors (DAP), and location registers such a HomeLocation Register (HLR) or Visitor Location Register (VLR). Furthermore,other network elements may be present to facilitate communicationbetween ANs 104, 106, 106A and wireless network 108, which are omittedfor clarity, including additional processing nodes, routers, gateways,and physical and/or wireless data links for carrying data among thevarious network elements.

Wireless devices 102, 102A, 102B can be any device configured tocommunicate over system 100 using a wireless interface. For example,wireless devices 102, 102A, 102B can include a remote terminal unit, acell phone, a smart phone, a computing platform such as a laptop,palmtop, or a tablet, a Personal Digital Assistant (PDA), or an internetaccess device, and combinations thereof. It is noted that while twowireless devices 102, 102A are illustrated in FIG. 1A and one wirelessdevice 102B is illustrated in FIG. 1B as being in communication with ANs104, 106 and/or 106A, any number of wireless devices can be implementedaccording to various exemplary embodiments disclosed herein.

Wireless devices 102, 102A, 102B can transmit and/or receive informationover system 100 using various communication services. These services caninclude various voice, data, and/or Multimedia Broadcast MulticastService (MBMS) services and applications. For example, mobile voiceservices, mobile data services, Push-to-Talk (PTT) services, internetservices, web-browsing, email, pictures, picture messaging, video, videomessaging, broadcast video, audio, voicemail, music MP3's, ring tones,stock tickers, news alerts, etc.

ANs 104, 106, 106A can be any network node configured to providecommunication between wireless devices 102, 102A, 102B and wirelessnetwork 108. ANs 104, 106, 106A can be short-range ANs or standard ANs.A short-range AN could include a microcell base station, a picocell basestation, a femtocell base station, or the like; a standard AN couldinclude a base transceiver station, a radio base station, an eNodeBdevice, or an enhanced eNodeB device, or the like. Smart antenna arrays(e.g., switched-beam, phased array, and/or adaptive array systems) withintelligent beam-steering may be deployed at and/or exploited at ANs104, 106, 106A. For example, ANs 104, 106, 106A may use Tx/Rx antennas122 of the smart antenna arrays to direct beams and/or beam patternstoward select wireless devices 102, 102A, 102B (or geographic areas)within a coverage area (i.e., minimum usable signal area) of ANs 104,106, 106A to increase signal-capturing power at the wireless devices102, 102A, 102B (or geographic areas), while suppressing and/ornullifying signals emanating to/from other wireless devices and/or ANs.ANs 104, 106, and/or 106B may use a beam-select node 124 and/orbeam-former node 122 to, for example, calculate beamforming weights,weight the magnitude and/or phase of individual antenna signalsbroadcast by Tx/Rx antennas 122, align beam main-lobes to DoA, etc.Beam-select node 124 and/or beam-former node 122 may be configured as anexemplary processing node 500, illustrated in FIG. 5. It is noted thatwhile two ANs 104, 106 are illustrated in FIG. 1A and one AN 106A isillustrated in FIG. 1B, any number of ANs can be implemented withinsystem 100.

Communication network 108 can be a wired and/or wireless communicationnetwork, and can comprise processing nodes, routers, gateways, andphysical and/or wireless data links for carrying data among variousnetwork elements, including combinations thereof, and can include aLocal Area Network (LAN), a Wide Area Network (WAN), and an internetwork(including the Internet). Communication network 108 can be capable ofcarrying data, for example, to support voice, PTT, broadcast video, anddata communications by a wireless device, for example, wireless devices102, 102A, 102B. Wireless network protocols can comprise Code DivisionMultiple Access (CDMA) 1×RTT, Global System for Mobile communications(GSM), Universal Mobile Telecommunications System (UMTS), High-SpeedPacket Access (HSPA), Evolution Data Optimized (EV-DO), EV-DO rev. A,Third Generation Partnership Project Long Term Evolution (3GPP LTE), andWorldwide Interoperability for Microwave Access (WiMAX). Wired networkprotocols that may be utilized by communication network 108 compriseEthernet, Fast Ethernet, Gigabit Ethernet, Local Talk (such as CarrierSense Multiple Access with Collision Avoidance), Token Ring, FiberDistributed Data Interface (FDDI), and Asynchronous Transfer Mode (ATM).Communication network 108 can also comprise additional base stations,controller nodes, telephony switches, internet routers, networkgateways, computer systems, communication links, or some other type ofcommunication equipment, and combinations thereof

Network node 110 can be any network node configured to communicateinformation and/or control information over system 100. For example,network node 110 can receive information from or transmit information towireless devices 102, 102A, 102B over system 100. For ease ofillustration, network node 110 is shown to be located within thebackhaul of system 100. However, network node 110 could alternatively bebetween ANs 104, 106, 106A and wireless network 108. Network node 110can be a standalone computing device, computing system, or networkcomponent, and can be accessible, for example, by a wired or wirelessconnection, or through an indirect connection such as through a computernetwork or wireless network. For example, network node 110 can include aMobility Management Entity (MME), a Home Subscriber Server (HSS), aPolicy Control and Charging Rules Function (PCRF), an Authentication,Authorization, and Accounting (AAA) node, a Rights Management Server(RMS), a Subscriber Provisioning Server (SPS), a policy server, etc. Oneof ordinary skill in the art would recognize that network node 110 isnot limited to any specific technology architecture, such as LTE, andcan be used with any network architecture and/or protocol.

Communication links 112, 114, 116, 118, 120 can be wired or wireless anduse various communication protocols such as Internet, Internet Protocol(IP), LAN, optical networking, Hybrid Fiber Coax (HFC), telephony, T1,or some other communication format—including combinations, improvements,or variations thereof. Wireless communication links can be a RadioFrequency (RF), microwave, infrared, or other similar signal, and canuse a suitable communication protocol, for example, GSM, CDMA, WiMAX, orLTE, or combinations thereof. Other wireless protocols can also be used.Links 112, 114, 116, 118, 120 can be direct link or might includevarious equipment, intermediate components, systems, and networks.

FIG. 2 illustrates a flow chart of an exemplary method for prioritizingANs and/or cell sectors for handover of a beam-formed (or candidate)wireless device in a wireless network. The method will be discussed withreference to the exemplary system 100 illustrated in FIG. 1A and theexemplary AN illustrated in FIG. 1B. However, the method forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device illustrated in FIG. 2 can be implemented withany suitable communication system. In addition, although FIG. 2 depictssteps performed in a particular order for purposes of illustration anddiscussion, the methods discussed herein are not limited to anyparticular order or arrangement. One skilled in the art, using thedisclosure provided herein, will appreciate that various steps of themethod can be omitted, rearranged, combined, and/or adapted in variousways.

Referring to FIG. 2, multiple beam-form enabled Tx/Rx antennas 122 maybe deployed at ANs 104, 106, 106A of wireless network 108 and may beconfigured to control a direction of a wavefront (i.e., of RF signals)by appropriately weighting the magnitude and phase of individual antennasignals (i.e., transmitted from Tx/Rx antennas 122). For example, AN104, 106, 106A may use individual Tx/Rx antennas 122 of the smartantenna array (e.g., switched-beam, phased array, and/or adaptive arraysystems) deployed at AN 104, 106, 106A, equipped with intelligentbeam-steering, to continuously control and/or radiate (i.e., direct)beams and/or beam patterns toward select wireless devices 102, 102A,102B using the individual Tx/Rx antennas 122 in the smart antenna arrayto contribute to a steered RF signal and/or wavefront. AN 104, 106, 106Ause the beams and/or beam patterns (i.e., the steered RF signals and/orwavefront) to achieve beamforming gains at the selected wireless devices102, 102A, 102B as the wireless devices 102, 102A, 102B move within aradio range of AN 104, 106, 106A. AN 104, 106, 106A can use thebeam-form enabled Tx/Rx antennas 122 of the smart antenna array tosuppress interfering signal(s) emanating to/from other wireless devicesand/or ANs by applying a beam pattern null from the beam-form enabledTx/Rx antennas 122 in the direction(s) of the interfering signal(s). AN104, 106, 106A may choose to “handoff” beam-formed (or candidate)wireless devices 102, 102B to a beam-form capable target AN 104, 106,106A and/or cell sectors of the beam-form capable target AN 104, 106,106A, when a beam-form load (e.g., a number of beam-formed wirelessdevices) at a source AN 104, 106, 106A meets (or exceeds) a threshold.

For example, at 202, wireless network 108 may select one or morebeam-form capable, neighboring ANs 106, 106A and/or cell sectors of thebeam-form capable, neighboring ANs 106, 106A from a pool of availablecandidate ANs 106, 106A and/or cell sectors. Source AN 104 may instructone or more wireless devices 102, 102B operating at an edge of a radiorange (i.e., minimum usable signal area) of AN 104 to measure and/orreport various detectable signal properties (e.g., CQI, RSSI, RSRP,RSRQ, SINR, etc.), Cell-IDs, etc., broadcast by ANs 106, 106A from thepool of candidate ANs 106, 106A on the UL at AN 104. The one or morewireless devices 102, 102B may also report an availability of ULair-interface SRS resources (e.g., SRS resource blocks allocatable towireless devices 102, 102B) on the UL at AN 104. From the reportedsignal properties, Cell-IDs, etc., associated with the pool of candidateANs 106, 106A, AN 104 (e.g., via beam-select 124 and/or beam-former 126)may select beam-form capable ANs 106 and/or cell sectors of thebeam-form capable ANs 106 from the pool of candidate ANs 106, 106Aand/or cell sectors of the pool of candidate ANs 106, 106A (e.g.,neighboring ANs and/or cell sectors of neighboring ANs whose reportedsignal properties, Cell-IDs (e.g., CSG-ID, etc.), meet a requirement atthe wireless device 102, 102B).

At 204, source AN 104 prioritizes the selected beam-form capable ANs 106and/or cell sectors of the beam-form capable ANs 106 for handover of thewireless device(s) 102, 102B based on an open beamforming seat. Forexample, source AN 104 (via wireless network 108 and/or network node110) may determine (or calculate) a beam-form load (e.g., a number ofbeam-formed wireless devices) at cell sectors of the selected beam-formcapable ANs 106. If the beam-form load at one or more cell sectors ofthe selected beam-form capable AN 106 and/or a total beam-form load forthe selected beam-form capable AN 106 meets (or exceeds) a threshold(i.e., a restricted number of beam-form seats), the cell sector of thebeam-form capable AN 106 and/or the beam-form capable AN 106 isde-prioritized for handover of the wireless devices 102, 102B. In otherwords, source AN 104 prioritizes cell sectors of the beam-form capableANs 106 and/or beam-form capable ANs 106 selected from the pool ofcandidate ANs 106, 106A based on an open beam-form seat at at least onecell sector of the beam-form capable AN 106 and/or at the beam-formcapable AN 106 (i.e., an overall beam-form load at AN 106 has not met orexceeded a restricted number of beam-form seats).

At 206, source AN 104 may perform a handover of the wireless devices102, 102B to prioritized cell sectors of the beam-form capable ANs 106with an open beam-form seat. For example, AN 104 can “handoff”beam-formed (or candidate) wireless devices 102, 102B (e.g., wirelessdevice 102A) to prioritized cell sectors of beam-form capable AN 106. AN106 may instruct wireless device 102A to report an availability of ULair-interface SRS resources (e.g., SRS resource blocks allocatable towireless device 102A) on the UL at Tx/Rx antennas 122 of AN 106. AN 106may use the reported SRS' to estimate (or determine) a DoA forwavefronts (or RF signals) emanating from wireless device 102A usingvarious techniques such as MUSIC and/or through estimation of signalparameters via ESPRIT, etc. Based on the DoA of the wavefronts (or RFsignals), AN 106 calculates beamforming weights; AN 106's Tx/Rx antennas122 (i.e., of the smart antenna array) use the calculated beamformingweights to radiate beams and/or beam patterns (e.g., formed by aligningbeam main-lobes to the DoA) on the DL toward wireless device 102A (e.g.,by weighting the magnitude and phase of individual antenna signalsbroadcast by Tx/Rx antennas 122 of AN's 106 antenna array). As wirelessdevice 102A moves within a radio range of AN 106, AN 106 via Tx/Rxantennas 122 may continuously control and/or radiate (i.e., direct)beams and/or beam patterns toward the wireless device 102A using theindividual Tx/Rx antennas 122 in the smart antenna array to contributeto a steered RF signal and/or wavefront. AN 106 uses the beams and/orbeam patterns (i.e., the steered RF signals and/or wavefront) to achievebeamforming gains at wireless device 102A, while applying a beam patternnull from the Tx/Rx antennas 122 in the direction of other wirelessdevices and/or ANs to suppress interfering signal(s) emanating to/fromother wireless devices and/or ANs.

FIG. 3 illustrates another exemplary communication system 300 forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device in a wireless network. System 300 cancomprise wireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316,ANs 318, 320, 322, gateway node 324, controller node 326, and wirelessnetwork 328. Other network elements may be present in the communicationsystem 300 to facilitate communication but are omitted for clarity, suchas base stations, base station controllers, gateways, MSCs, DPAs, andlocation registers such as a HLR or VLR. Furthermore, other networkelements may be present to facilitate communication, such as between ANs318, 320, 322 and wireless network 328, which are omitted for clarity,including additional processing nodes, routers, gateways, and physicaland/or wireless data links for carrying data among the various networkelements.

Wireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316 can be anydevice configured to communicate over system 300 using a wirelessinterface. For example, wireless devices 302, 302A, 304, 306, 308, 310,312, 314, 316 can include a remote terminal unit, a cell phone, a smartphone, a computing platform such as a laptop, palmtop, or a tablet, aPDA, or an internet access device, and combinations thereof. Wirelessdevices 302, 302A, 304, 306, 308, 310, 312, 314, 316 can include one ormore Tx/Rx antennas (not shown) for transmitting and receiving data oversystem 300. Each Tx/Rx antenna can be associated with the same ordifferent frequency bands, the same or different radio accesstechnologies, the same or different network providers, and/or the sameor different services. For example, wireless devices 302, 302A, 304,306, 308, 310, 312, 314, 316 can include Tx/Rx antennas that areassociated with one or more of the following: CDMA, GSM, WiMAX, LTE,HSDPA, IEEE 802.11, WiFi, Bluetooth, Zigbee, IrDA, MBMS, etc.

Wireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316 can beconnected with ANs 318, 320, 322 through communication links(illustrated only between AN 318 and wireless device 302 and AN 322 andwireless device 302A). For example, the links 352, 354 can use variouscommunication media, such as air, space, metal, optical fiber, or someother signal propagation path - including combinations thereof. Thelinks 352, 354 may comprise many different signals sharing the samelink. The links 352, 354 could include multiple signals operating in asingle “airpath” comprising beacon signals, user communications,communication sessions, overhead communications, frequencies, timeslots,transportation ports, logical transportation links, network sockets,packets, or communication directions. For example, user communicationbetween wireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316and ANs 318, 320, 322 could share the same representative wireless link,but be transferred over different communication sessions, frequencies,timeslots, packets, ports, sockets, logical transport links, or indifferent directions - including combinations thereof

Wireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316 cantransmit and/or receive information over system 300 using variouscommunication services. These services can include various voice, data,and/or MBMS services and applications. For example, mobile voiceservices, mobile data services, PTT services, internet services, webbrowsing, email, pictures, picture messaging, video, video messaging,broadcast video, audio, voicemail, music, MP3's, ring tones, stocktickers, new alerts, etc.

ANs 318, 320, 322 can be any network node configured to providecommunication between wireless devices 302, 302A, 304, 306, 308, 310,312, 314, 316 and wireless network 328. ANs 318, 320, 322 can beshort-range ANs or standard ANs. A short-range AN could include amicrocell base station, a picocell base station, a femtocell basestation, or the like; a standard AN could include a base transceiverstation, a radio base station, an eNodeB device, or an enhanced eNodeBdevice, or the like. In an exemplary embodiment, a picocell AN can havea coverage area of approximately a half a kilometer and an output powerof less than one watt; a macrocell AN can have a coverage area in therange of approximately five kilometers to thirty-five kilometers and anoutput power in the tens of watts. In yet another exemplary embodiment,a femtocell AN can have a coverage area in the range of fifty totwo-hundred meters and an output power in the range of 0.5 to 1 watts.Femtocell AN can be cellular AN or WiFi AN. In addition, a wirelessdevice configured to enter a hotspot mode can be a femtocell AN. ANs318, 320, 322 may divided into multiple cell sectors A1, B1, C1, A2, B2,C2, A3, B3, C3. While ANs 318, 320, 322 are illustrated in FIG. 3 asbeing divided into three cell sectors A1, B1, C1, A2, B2, C2, A3, B3,C3, ANs 318, 320, 322 may be divided into any number of cell sectors.Smart antenna arrays (e.g., switched-beam, phased array, and/or adaptivearray systems) with intelligent beam-steering may be deployed at and/orexploited at ANs 318, 320, 322. For example, ANs 318, 320, 322 may useTx/Rx antennas (illustrated in FIG. 1B) of the smart antenna arrays todirect beams and/or beam patterns toward select wireless devices 302,302A, 304, 306, 308, 310, 312, 314, 316 (or geographic areas) within aradio range (i.e., minimum usable signal area) 356, 358, 360 of ANs 318,320, 322 to increase signal-capturing power at the wireless devices 302,302A, 304, 306, 308, 310, 312, 314, 316 (or within the geographicareas), while suppressing and/or nullifying signals emanating to/fromother wireless devices and/or ANs. ANs 318, 320, 322 may use abeam-select node (illustrated in FIG. 1B) and/or beam-former node(illustrated in FIG. 1B) to, for example, calculate beamforming weights,weight the magnitude and/or phase of individual antenna signalsbroadcast by Tx/Rx antennas (of a smart antenna array), align beammain-lobes to DoA, etc. The beam-select node and/or beam-former node maybe configured as an exemplary processing node 500 (illustrated in FIG.5). It is noted that while three ANs 318, 320, 322 are illustrated inFIG. 3, any number of ANs can be implemented within system 300.

ANs 318, 320, 322 can comprise a processor and associated circuitry toexecute or direct the execution of computer-readable instructions toobtain information. ANs 318, 320, 322 can retrieve and execute softwarefrom storage, which can include a disk drive, a flash drive, memorycircuitry, or some other memory device, and which can be local orremotely accessible. The software comprises computer programs, firmware,or some other form of machine-readable instructions, and may include anoperating system, utilities, drivers, network interfaces, applications,or some other type of software, including combinations thereof. ANs 318,320, 322 can receive instructions and other input at a user interface.

Gateway node 324 can be any network node configured to interface withother network nodes using various protocols. Gateway node 324 cancommunicate user data over system 300. Gateway node 324 can be astandalone computing device, computing system, or network component, andcan be accessible, for example, by a wired or wireless connection, orthrough an indirect connection such as through a computer network orcellular network. For example, gateway node 324 can include a ServingGateway (SGW) and/or a Public Data Network Gateway (PGW), etc. One ofordinary skill in the art would recognize that gateway node 324 is notlimited to any specific technology architecture, such as LTE and can beused with any network architecture and/or protocol.

Gateway node 324 can comprise a processor and associated circuitry toexecute or direct the execution of computer-readable instructions toobtain information. Gateway node 324 can retrieve and execute softwarefrom storage, which can include a disk drive, a flash drive, memorycircuitry, or some other memory device, and which can be local orremotely accessible. The software comprises computer programs, firmware,or some other form of machine-readable instructions, and may include anoperating system, utilities, drivers, network interfaces, applications,or some other type of software, including combinations thereof. Gatewaynode 324 can receive instructions and other input at a user interface.

Controller node 326 can be any network node configured to communicateinformation and/or control information over system 300. Controller node326 can be configured to transmit control information associated with ahandover procedure. Controller node 326 can be a standalone computingdevice, computing system, or network component, and can be accessible,for example, by a wired or wireless connection, or through an indirectconnection such as through a computer network or cellular network. Forexample, controller node 326 can include a MME, a HSS, a PCRF, an AAAnode, a RMS, a SPS, a policy server, etc. One of ordinary skill in theart would recognize that controller node 326 is not limited to anyspecific technology architecture, such as LTE and can be used with anynetwork architecture and/or protocol.

Controller node 326 can comprise a processor and associated circuitry toexecute or direct the execution of computer-readable instructions toobtain information. Controller node 326 can retrieve and executesoftware from storage, which can include a disk drive, a flash drive,memory circuitry, or some other memory device, and which can be local orremotely accessible. The software comprises computer programs, firmware,or some other form of machine-readable instructions, and may include anoperating system, utilities, drivers, network interfaces, applications,or some other type of software, including combinations thereof.Controller node 326 can receive instructions and other input at a userinterface.

AN 318 may be connected with gateway node 324 through communication link330 and with controller node 326 through communication link 332. AN 318may be connected with ANs 320, 322 through communication links 334, 336.AN 320 may be connected with gateway node 324 through communication link338 and with controller node 326 through communication link 340. AN 320may be connected with AN 322 through communication link 342. AN 322 maybe connected with gateway node 324 through communication link 344 andwith controller node 326 through communication link 346. Gateway node324 may be connected with controller node 326 through communication link348 and with wireless network 328 through communication link 350. Links330, 332, 334, 336, 338, 340, 342, 344, 346, 348, 350 can be wired orwireless and use various communication protocols such as Internet, IP,LAN, optical networking, HFC, telephony, T1, or some other communicationformat—including combinations, improvements, or variations thereof.Links 330, 332, 334, 336, 338, 340, 342, 344, 346, 348, 350 can be a RF,microwave, infrared, or other similar signal, and can use a suitablecommunication protocol, for example, GSM, CDMA, WiMAX, or LTE, orcombinations thereof. Other wireless protocols can also be used. Links330, 332, 334, 336, 338, 340, 342, 344, 346, 348, 350 can be a directlink or might include various equipment, intermediate components,systems, and networks.

Wireless network 328 can be a wired and/or wireless communicationnetwork, and can comprise processing nodes, routers, gateways, andphysical and/or wireless data links for carrying data among variousnetwork elements, including combinations thereof, and can include a LANor WAN, and an internetwork (including the internet). Wireless network328 can be capable of carrying data, for example, to support voice, PTT,broadcast video, and data communications by a wireless device, such aswireless devices 302, 302A, 304, 306, 308, 310, 312, 314, 316. Wirelessnetwork protocols can comprise MBMS, CDMA ixRTT, GSM, UMTS, HSPA, EV-DO,EV-DO rev. A, 3GPP LTE, and WiMAX. Wired network protocols that may beutilized by wireless network 328 comprise Ethernet, Fast Ethernet,Gigabit Ethernet, Local Talk (such as Carrier Sense Multiple Access withCollision Avoidance), Token Ring, FDDI, ATM. Wireless network 328 canalso comprise additional base stations, controller nodes, telephonyswitches, internet routers, network gateways, computer systems,communication links, or some other type of communication equipment, andcombinations thereof

FIG. 4 illustrates another flow chart of an exemplary method forprioritizing ANs and/or cell sectors for handover of a beam-formed (orcandidate) wireless device in a wireless network. The method will bediscussed with reference to the exemplary system 300 illustrated in FIG.3. But, the method for prioritizing ANs and/or cell sectors for handoverof a beam-formed (or candidate) wireless device in a wireless networkillustrated in FIG. 4 can be implemented in the exemplary system 100illustrated in FIGS. 1A and 1B, or with any suitable communicationsystem. In addition, although FIG. 4 depicts steps performed in aparticular order for purposes of illustration and discussion, themethods discussed herein are not limited to any particular order orarrangement. One skilled in the art, using the disclosure providedherein, will appreciate that various steps of the method can be omitted,rearranged, combined, and/or adapted in various ways.

Referring to FIG. 4, multiple beam-form enabled Tx/Rx antennas(illustrated in FIG. 1B) of a smart antenna array (e.g., switched-beam,phased array, and/or adaptive array systems) may be deployed at ANs 318,322 of wireless network 328. The Tx/Rx antennas may be equipped withintelligent beam-steering and employ an algorithm for calculatingoptimum beamforming weights (e.g., based on DoA, AoA, and/or channelestimation of wavefronts and/or RF signals arriving from select wirelessdevices); For example, AN's 318, 322 Tx/Rx antennas (i.e., of the smartantenna array) use the calculated beamforming weights to control and/orradiate (i.e., to direct) beams and/or beam patterns (e.g., formed byaligning beam main-lobes to a DoA) on the DL toward wireless devices302, 312, 314, and/or 316 (e.g., by weighting the magnitude and phase ofindividual antenna signals broadcast by Tx/Rx antennas of AN's 318, 322smart antenna array). As wireless devices 302, 312, 314, and/or 316 movewithin a radio range 356, 358 of ANs 318, 322, AN's 318, 322 use theTx/Rx antennas to continuously control and/or radiate (i.e., direct)beams and/or beam patterns toward the wireless devices 302, 312, 314,and/or 316 (i.e., steered RF signals and/or wavefronts) to achievebeamforming gains at wireless devices 302, 312, 314, and/or 316, whileapplying a beam pattern null from the Tx/Rx antennas in the direction ofother wireless devices and/or ANs to suppress interfering signal(s)emanating to/from other wireless devices and/or ANs.

At 402, source AN 318 may select one or more candidate cell sectors A1,B1, C1, A2, B2, C2, A3, B3, C3 of an AN 318, 320, 322 from a pool ofneighboring cell sectors A1, B1, C1, A2, B2, C2, A3, B3, C3 of ANs 318,320, 322. For example, source AN 318 may experience a beam-form load atone or more cell sectors A1, B1, C1 and/or a total beam-form load at theAN 318 that meets (or exceeds) a threshold (i.e., a maximum number ofbeam-form wireless devices 302, 316 supported at AN 318 and/or at eachof the one or more cell sectors A1, B1, C1 as a function of a SRS periodand/or SRS resource blocks allocatable to connected wireless devices302, 316, for example, for one OEM with an SRS period of 5 millisecondsthe maximum number of beam-form wireless devices is 48). When thebeam-form load meets (or exceeds) the threshold, wireless network 328may trigger AN 318 to instruct one or more wireless devices 302operating at an edge of a radio range 356 and/or cell sector A1, B1, C1boundary of AN 318 to measure and/or report detectable signal properties(e.g., CQI, RSSI, RSRP, RSRQ, SINR, etc.), Cell-IDs, etc., broadcast byneighboring ANs 320, 322 and/or cell sectors B1, C1, B2, C2, A3, B3 of acurrent cell sector Al of the one or more wireless devices 302 (i.e.,pool of candidate ANs and/or cell sectors). The one or more wirelessdevices 302 may also report an availability of UL air-interface SRSresources (e.g., SRS resource blocks allocatable to wireless device 302)on the UL at AN 318.

At 404-408, source AN 318 may prioritize the pool of candidate ANs 318,320, 322 and/or cell sectors B1, C1, B2, C2, A3, B3 for handover of theone or more wireless devices 302 based on an open beamforming seat. Forexample, source AN 318 uses the reported signal properties, Cell-IDs,etc., associated with the pool of candidate ANs 318, 320, 322 and/orcell sectors B1, C1, B2, C2, A3, B3 to select beam-form capable ANs 318,322 and/or cell sectors C1, A3, B3 from the pool of candidate ANs 318,320, 322 and/or cell sectors B1, C1, B2, C2, A3, B3. For each of thebeam-form capable ANs 318, 322 and/or cell sectors C1, A3, B3, source AN318 may calculate (or determine) a beam-form load (i.e., whether or notthe AN 318, 322 and/or cell sector C1, A3, B3 meets or exceeds athreshold number of beam-form wireless devices supported at AN 318, 322and/or cell sectors C1, A3, B3 as a function of a SRS period). If thebeam-form load at AN 318, 322 and/or cell sector C1, A3, B3 meets orexceeds the threshold, the AN 318 and/or cell sector C1 isde-prioritized for handover of the wireless device 302. In other words,source AN 318 prioritizes ANs 322 and/or cell sectors A3, B3 from thepool of candidate ANs 318, 320, 322 and/or cell sectors B1, C1, B2, C2,A3, B3 based on an open beam-form seat. In some instances, one or moreANs 322 and/or cell sectors A3, B3 may be prioritized for handover ofthe wireless device 302. For example, source AN 318 may determine thatboth cell sectors A3, B3 of AN 322 have at least one open beam-formseat. If the cell sectors A3, B3 of AN 322 both offer a similar RSRP orother signal quality indicator and/or have a similar overall loading orbeam-form load, AN 318 may select the “most-open” (i.e., highest numberof available beam-form seats) cell sector A3 of AN 322 for handover ofwireless device 302.

At 410, source AN 318 may perform a handover of the one or more wirelessdevices 302 to the prioritized AN 322 and/or cell sector A3 that has atleast one open beam-form seat and/or that is “most-open”. For example,AN 318 can “handoff” beam-formed (or candidate) wireless device 302(i.e., illustrated as wireless device 302A) to the prioritized beam-formcapable AN 322 and/or cell sector A3. AN 322 may instruct wirelessdevice 302A to report an availability of UL air-interface SRS resources(e.g., SRS resource blocks allocatable to wireless device 302A) on theUL at Tx/Rx antennas of AN 322. AN 322 may use the reported SRS' toestimate (or determine) a DoA for wavefronts (or RF signals) emanatingfrom wireless device 302A using various techniques such as MUSIC and/orthrough estimation of signal parameters via ESPRIT, etc. The Tx/Rxantennas at AN 322 may be equipped with intelligent beam-steering andemploy an algorithm for calculating optimum beamforming weights (e.g.,based on DoA, AoA, and/or channel estimation of wavefronts and/or RFsignals arriving from wireless device 302A); For example, AN 322's Tx/Rxantennas (i.e., of the smart antenna array) use the calculatedbeamforming weights to control and/or radiate (i.e., to direct) beamsand/or beam patterns (e.g., formed by aligning beam main-lobes to a DoA)on the DL toward wireless device 302A (e.g., by weighting the magnitudeand phase of individual antenna signals broadcast by Tx/Rx antennas ofAN 322's smart antenna array). As wireless device 302A moves within aradio range 358 of AN 322, AN 322 uses the Tx/Rx antennas tocontinuously control and/or radiate (i.e., direct) beams and/or beampatterns toward the wireless device 302A (i.e., steered RF signalsand/or wavefronts) to achieve beamforming gains at wireless device 302A,while applying a beam pattern null from the Tx/Rx antennas in thedirection of other wireless devices and/or ANs to suppress interferingsignal(s) emanating to/from other wireless devices and/or ANs.

FIG. 5 illustrates an exemplary processing node 500 in a communicationsystem. Processing node 500 comprises communication interface 502, userinterface 504, and processing system 506 in communication withcommunication interface 502 and user interface 504. Processing node 500can be configured to determine a communication AN for a wireless device.Processing system 506 includes storage 508, which can comprise a diskdrive, flash drive, memory circuitry, or other memory device. Storage508 can store software 510 which is used in the operation of theprocessing node 500. Storage 508 may include a disk drive, flash drive,data storage circuitry, or some other memory apparatus. Software 510 mayinclude computer programs, firmware, or some other form ofmachine-readable instructions, including an operating system, utilities,drivers, network interfaces, applications, or some other type ofsoftware. Processing system 506 may include a microprocessor and othercircuitry to retrieve and execute software 510 from storage 508.Processing node 500 may further include other components such as a powermanagement unit, a control interface unit, etc., which are omitted forclarity. Communication interface 502 permits processing node 500 tocommunicate with other network elements. User interface 504 permits theconfiguration and control of the operation of processing node 500.

Examples of processing node 500 include ANs 104, 106, 106A, 318, 320,322, beam-select node 124, beam-former node 126, network node 110,gateway node 324, and controller node 326. Processing node 500 can alsobe an adjunct or component of a network element, such as an element ofANs 104, 106, 106A, 318, 320, 322, beam-select node 124, beam-formernode 126, network node 110, gateway node 324, and controller node 326.Processing node 500 can also be another network element in acommunication system. Further, the functionality of processing node 500can be distributed over two or more network elements of a communicationsystem.

The exemplary systems and methods described herein can be performedunder the control of a processing system executing computer-readablecodes embodied on a computer-readable recording medium or communicationsignals transmitted through a transitory medium. The computer-readablerecording medium is any data storage device that can store data readableby a processing system, and includes both volatile and nonvolatilemedia, removable and non-removable media, and contemplates mediareadable by a database, a computer, and various other network devices.

Examples of the computer-readable recording medium include, but are notlimited to, read-only memory (ROM), random-access memory (RAM), erasableelectrically programmable ROM (EEPROM), flash memory or other memorytechnology, holographic media or other optical disc storage, magneticstorage including magnetic tape and magnetic disk, and solid statestorage devices. The computer-readable recording medium can also bedistributed over network-coupled computer systems so that thecomputer-readable code is stored and executed in a distributed fashion.The communication signals transmitted through a transitory medium mayinclude, for example, modulated signals transmitted through wired orwireless transmission paths.

The above description and associated figures teach the best mode of theinvention. The following claims specify the scope of the invention. Notethat some aspects of the best mode may not fall within the scope of theinvention as specified by the claims. Those skilled in the art willappreciate that the features described above can be combined in variousways to form multiple variations of the invention, and that variousmodifications may be made to the configuration and methodology of theexemplary embodiments disclosed herein without departing from the scopeof the present teachings. Those skilled in the art also will appreciatethat various features disclosed with respect to one exemplary embodimentherein may be used in combination with other exemplary embodiments withappropriate modifications, even if such combinations are not explicitlydisclosed herein. As a result, the invention is not limited to thespecific embodiments described above, but only by the following claimsand their equivalents.

What is claimed is:
 1. A method for handover of at least one wirelessdevice, the method comprising: verifying that one or more sectors offerbeamforming; generating a list of prioritized sectors based on theverification, the sectors being prioritized based on an open beamformingseat; calculating a beam-form load for each of the sectors; andselecting the sector having a beam-form load meeting a set criteria forhandover of the at least one wireless device.
 2. The method of claim 1,wherein the set criteria is a sector having a greatest number of openbeam-form seats as compared to other prioritized sectors.
 3. The methodof claim 1, wherein the prioritized sectors are within a radio range ofthe at least one wireless device.
 4. The method of claim 1, whereinhandover of the at least one wireless device is triggered at a firstsector in response to the beam-form load meeting the set criteria. 5.The method of claim 4, wherein the criteria is a number of beam-formwireless devices supported at the first sector as a function of anSounding Reference Signal (SRS) period.
 6. The method of claim 4,wherein the selected the first sector instructs the at least onewireless device to report an availability of uplink (UL) air-interfaceSounding Reference Signal (SRS) resources at the first sector.
 7. Themethod of claim 4, further comprising: instructing the at least onewireless device to measure detectable signal properties of the one ormore sectors, wherein the signal properties include at least one of aChannel Quality Indicator (CQI), Received Signal Strength Indicator (RSSI), and Signal-to-Interference-Plus-Noise Ratio (SINR).
 8. A system forhandover of at least one wireless device, the system comprising: amemory; and a processor configured to: verify that one or more sectorsoffer beamforming; generate a list of prioritized sectors based on theverification, the sectors being prioritized based on an open beamformingseat; calculate a beam-form load for each of the sectors; and select thesector having a beam-form load meeting a set criteria for handover ofthe at least one wireless device.
 9. The system of claim 8, wherein theset criteria is a sector having a greatest number of open beam-formseats as compared to other prioritized sectors.
 10. The system of claim8, wherein the prioritized sectors are within a radio range of the atleast one wireless device.
 11. The system of claim 8, wherein handoverof the at least one wireless device is triggered at a first sector inresponse to the beam-form load meeting the set criteria.
 12. The systemof claim 11, wherein the criteria is a number of beam-form wirelessdevices supported at the first sector as a function of an SoundingReference Signal (SRS) period.
 13. The system of claim 11, wherein thefirst sector is configured to instruct the at least one wireless deviceto report an availability of uplink (UL) air-interface SoundingReference Signal (SRS) resources at the first sector.
 14. The system ofclaim 11, where in the processor is further configured to: instruct theat least one wireless device to measure detectable signal properties ofthe one or more sectors, wherein the signal properties include at leastone of a Channel Quality Indicator (CQI), Received Signal StrengthIndicator (RS SI), and Signal-to-Interference-Plus-Noise Ratio (SINR).15. A processing node for performing handover of at least one wirelessdevice, the processing node comprising: a processor; and a memorystoring instructions for the processor, the instructions comprising:verifying that one or more sectors offer beamforming; generating a listof prioritized sectors based on the verification, the sectors beingprioritized based on an open beamforming seat; calculating a beam-formload for each of the sectors; and selecting the sector having abeam-form load meeting a set criteria for handover of the at least onewireless device.
 16. The processing node of claim 15, wherein the setcriteria is a sector having a greatest number of open beam-form seats ascompared to other prioritized sectors.
 17. The processing node of claim15, wherein handover of the at least one wireless device is triggered ata first sector in response to the beam-form load meeting the setcriteria.
 18. The processing node of claim 17, wherein the criteria is anumber of beam-form wireless devices supported at the first sector as afunction of an Sounding Reference Signal (SRS) period.
 19. Theprocessing node of claim 17, wherein the first sector instructs the atleast one wireless device to report an availability of uplink (UL)air-interface Sounding Reference Signal (SRS) resources at the firstsector.
 20. The processing node of claim 17, wherein the instructionsfurther comprise: instructing the at least one wireless device tomeasure detectable signal properties of the one or more sectors, whereinthe signal properties include at least one of a Channel QualityIndicator (CQI), Received Signal Strength Indicator (RS SI), andSignal-to-Interference-Plus-Noise Ratio (SINR).